1. Field of the Invention
The invention relates generally to the field of vehicle occupant notification systems. More particularly, the invention relates to driver notification systems having a road mounted component.
2. Discussion of the Related Art
Traveling on interstate highways requires a constantly high level of driver attention to reduce the risk of an accident. There are specific periods during which the opportunity for driver error and the potential for an accident is above average. Alerting the driver to the presence of hazardous conditions could reduce the risk or severity of an accident. Entering and exiting from interstate are especially hazardous periods, which require an alert and informed driver.
Run-off-the-road accidents are among the most frequent types of highway accidents. Tired, sleepy or inattentive drivers often fail to guide their vehicles within the proper lane, and almost every driver, on some occasion, has been distracted enough to run off the edge of the road onto the shoulder. A means is needed to warn such a driver of deviation from the intended path before the excursion becomes an accident.
Unfortunately, there are not enough reliable data on encroachment (the specific technical term used in highway safety literature to describe this type of incident) to allow highway engineers and others interested in highway safety to evaluate the frequency and severity of encroachments that do not result in accidents. The current state of the art of encroachment data collection has been described as "look for tire tracks." What is needed is a cost-effective way to collect sufficient data to allow evaluation or correction of existing situations that lead to encroachment and run-off-the-road accidents.
Accidents involving trains and automobiles are often tragic and fatal. Even though railroad crossings are clearly marked, many do not have flashing lights and audible tones because of the additional costs.
Safe driving rules and road signs are not adequate to prevent some classes of highway accidents. As we know, a moment's inattentiveness, distractions, and drowsiness can lead to accidents and fatalities. Other forms of sensory input such as bells at railroad crossings and rumble strips at dangerous intersections and sections of highway are used in special cases to supplement and complement visual symbols.
Most approaches to driver signaling require an on-board electronic device to detect and decode signals sent by road-side equipment. Legislation to require additional safety equipment for vehicles although often quite justified requires a significant effort and always adds to vehicle costs (e.g., air bags, seat belts, and center-mounted brake light).